In the container transport industry, one known device for loading a box or container onto a vehicle is a hook-hoist. This essentially consists of an L-shaped arm having a container-engaging hook at one end and being pivotally connected to the vehicle at its other end. Rollers are mounted at the rear of the vehicle. To load a container, the arm is pivoted rearwardly and maneuvered until the hook engages with the container. As the arm is pivoted forwardly, the container is lifted, front end first, and pulled forward until it contacts the rollers, at which point the container both rolls forwardly along and pivots about the rollers. Ultimately, the arm returns to its rest position and the container sits atop the container supports which, at the rear of the vehicle, consists of the rollers. The arm also is telescopically extendable at this stage whereby the container may then be pulled forward to a more desirable transport position.
Containers are made in different sizes, for example, 10, 12, 14, 16 or 18 feet long. While a hauler may wish to haul all sizes of containers on one truck, federal safety laws prohibit an overhanging load from extending more than 24 inches beyond the rear bumper. A given hook hoist vehicle can therefore only accommodate a specific range of containers. For example, one vehicle might be able to carry nothing shorter than a 12 foot box and, legally, nothing longer than a 14 foot box. Further, because of the manner in which a hook hoist dumps the container load (by pivoting the arm and the container rearwardly until the tail end of the container touches ground), the latter vehicle could achieve a fairly steep dump angle with a 12 foot container (facilitating dumping). But because the tail end of a 14 foot container extends rearwardly farther, it would touch ground sooner upon its being pivoted and pushed rearwardly, and a lesser dump angle would result. Dumping the 14 foot box's contents is therefore less efficient. In further contrast, only a very limited dump angle could be achieved with a 16 foot box on this size truck, and effective dumping would be practically impossible. Furthermore, the rear end of a 16 foot box (or anything longer than a 14 foot box) would extend farther past this vehicle's rear bumper than allowed by federal law. Consequently, each size of container is best fitted with a certain length truck having constructed thereon a correspondingly dimensioned hook hoist. This requires construction of a differently sized hook hoist for each different vehicle length.
What is needed is a truck and/or hook hoist design that can facilitate the construction of the vehicle mounted hook hoist.